Most electronic devices such as servers, computers and the like, are made up of various electronic components within some sort of metal box or chassis. In particular, many servers now fit on individual circuit boards known as “blades” and are placed within a chassis conforming to the Advanced Telecom Computing Architecture (ATCA) 3.0 standard, published January 2003. The ATCA standard defines an open switch fabric-based platform delivering an industry standard high performance, fault tolerant, and scalable solution for next generation telecommunications and data center equipment. The development of the ATCA standard is overseen by the PCI Industrial Computer Manufacturers Group (PICMG)—the same group that created the highly successful Compact PCI standard.
The ATCA 3.0 base specification defines the physical and electrical characteristics of an off-the-shelf, modular chassis based on switch fabric connections between hot-swappable blades. Specifically, the ATCA 3.0 base specification defines the frame (rack) and shelf (chassis) form factors, core backplane fabric connectivity, power, cooling, management interfaces, and the electromechanical specification of the ATCA-compliant boards. The ATCA 3.0 base specification also defines a power budget of 200 Watts (W) per blade, enabling high performance servers with multi-processor architectures and multi gigabytes of on-board memory.
During operation, each blade's components generate heat. Existing form factors for blade-type computers rely on forced convection for cooling. In blade computers conforming to the ATCA 3.0 specification, large solid metal heatsinks are used together with forced convection to cool high-power processors. The volume of the heatsinks, however, is limited due to height restrictions and, based on current chassis technologies, the volumetric airflow rate is also limited. As such the cooling capacity of the heatsink is extremely limited, thus limiting the usage of higher performance (and higher heat generating) processors. In addition, to extend the cooling capacity the processors must be placed at the location of the coolest air temperature, so heat generating devices are confined to being placed at the lower part of the blade so cool air flowing into the chassis will immediately flow over the heatsinks.